A method for ramping a switched capacitor power amplifier is disclosed, where the switched capacitor power amplifier comprises a plurality of capacitors in a capacitor bank, and where a number of the capacitors in the capacitor bank are activated. The method comprises changing the number of capacitors in the capacitor bank that are activated, maintaining the changed number of activated capacitors in the capacitor bank for a period of time, and repeating the changing and maintaining, where a length of the period of time is varied between at least two repetitions of the maintaining.

A technique relates to a quantum-limited microwave amplifier. A Josephson ring modulator (JRM) is connected to a first lumped-element resonator. The first lumped-element resonator includes one or more first lumped elements. A second lumped-element resonator is connected to the JRM, and the second lumped-element resonator includes one or more second lumped elements. The JRM, the first lumped-element resonator, and the second-lumped element resonator form a Josephson parametric converter (JPC). The one or more first lumped elements and the one or more second lumped elements have a value that is the same, thereby configuring the JPC to be spectrally degenerate.

A technique relates to a quantum-limited microwave amplifier. A Josephson ring modulator (JRM) is connected to a first lumped-element resonator. The first lumped-element resonator includes one or more first lumped elements. A second lumped-element resonator is connected to the JRM, and the second lumped-element resonator includes one or more second lumped elements. The JRM, the first lumped-element resonator, and the second-lumped element resonator form a Josephson parametric converter (JPC). The one or more first lumped elements and the one or more second lumped elements have a value that is the same, thereby configuring the JPC to be spectrally degenerate.

A radio frequency (RF) wave generator includes a nonlinear transmission line and a pulse generator. The nonlinear transmission line has in order an input section, a magnetic section, and an output section. The magnetic section includes a nonlinear magnetic material. The pulse generator is configured to provide an input pulse to the input section which is converted to an RF wave by the nonlinear transmission line. A waveform of the input pulse is such that the generated RF wave is parametrically amplified.

A radio frequency (RF) wave generator includes a nonlinear transmission line and a pulse generator. The nonlinear transmission line has in order an input section, a magnetic section, and an output section. The magnetic section includes a nonlinear magnetic material. The pulse generator is configured to provide an input pulse to the input section which is converted to an RF wave by the nonlinear transmission line. A waveform of the input pulse is such that the generated RF wave is parametrically amplified.

A technique relates to a quantum-limited microwave amplifier. A Josephson ring modulator (JRM) is connected to a first lumped-element resonator. The first lumped-element resonator includes one or more first lumped elements. A second lumped-element resonator is connected to the JRM, and the second lumped-element resonator includes one or more second lumped elements. The JRM, the first lumped-element resonator, and the second-lumped element resonator form a Josephson parametric converter (JPC). The one or more first lumped elements and the one or more second lumped elements have a value that is the same, thereby configuring the JPC to be spectrally degenerate.

A technique relates to a quantum-limited microwave amplifier. A Josephson ring modulator (JRM) is connected to a first lumped-element resonator. The first lumped-element resonator includes one or more first lumped elements. A second lumped-element resonator is connected to the JRM, and the second lumped-element resonator includes one or more second lumped elements. The JRM, the first lumped-element resonator, and the second-lumped element resonator form a Josephson parametric converter (JPC). The one or more first lumped elements and the one or more second lumped elements have a value that is the same, thereby configuring the JPC to be spectrally degenerate.

A technique relates to a quantum-limited microwave amplifier. A Josephson ring modulator (JRM) is connected to a first lumped-element resonator. The first lumped-element resonator includes one or more first lumped elements. A second lumped-element resonator is connected to the JRM, and the second lumped-element resonator includes one or more second lumped elements. The JRM, the first lumped-element resonator, and the second-lumped element resonator form a Josephson parametric converter (JPC). The one or more first lumped elements and the one or more second lumped elements have a value that is the same, thereby configuring the JPC to be spectrally degenerate.

A technique relates to a quantum-limited microwave amplifier. A Josephson ring modulator (JRM) is connected to a first lumped-element resonator. The first lumped-element resonator includes one or more first lumped elements. A second lumped-element resonator is connected to the JRM, and the second lumped-element resonator includes one or more second lumped elements. The JRM, the first lumped-element resonator, and the second-lumped element resonator form a Josephson parametric converter (JPC). The one or more first lumped elements and the one or more second lumped elements have a value that is the same, thereby configuring the JPC to be spectrally degenerate.

According to some aspects, a quantum circuit is provided including a plurality of non-linear circuit elements coupled together in series and in parallel, such that at least two of the circuit elements are coupled together in series and at least two of the circuit elements are coupled together in parallel, wherein the quantum circuit is configured to act as an amplifier.